DFT Analysis of the Indium-Antimony-Vacancy Cluster in Silicon
A cluster comprising of indium, antimony and a vacancy in silicon is analysed using the planewave pseudopotential technique. This cluster has a strong binding energy that inhibits indium diffusion after high temperature anneal cycles. Difficulties associated with the simulation of a vacancy using the supercell approach are initially highlighted. In comparison, the indium-antimony-vacancy cluster reveals stronger distortions and reduction in relaxation volume. The indium atom in the relaxed cluster shows nearly six-fold coordination whereas the antimony atom acquires four neighbours. Due to the low symmetry of the centre, in constrast to the isolated vacancy there is no propensity for a Jahn-Teller effect. It gives rise to two defect levels in the bandgap.
David J. Fisher
M.M. D. Souza and J. P. Goss, "DFT Analysis of the Indium-Antimony-Vacancy Cluster in Silicon", Defect and Diffusion Forum, Vols. 245-246, pp. 29-38, 2005